1. Field of the Invention
The invention relates to a collision predicting apparatus and a collision predicting method for predicting whether an own vehicle and a collision target will collide.
2. Description of the Related Art
With regard to collision prediction systems, related-art technologies are disclosed in, for example, Japanese Patent Application Laid-Open Publication No. 8-254576. In a collision prediction system in the related-art technology, ultrasonic waves are transmitted, and a relative velocity of the own vehicle with respect to a specific obstacle (subject target) present around the own vehicle is calculated with high accuracy from the time needed to receive Doppler waves reflected from the obstacle (subject target). For the calculation of a relative velocity, this collision prediction system averages data that serve as a basis for the calculation of a relative velocity in order to select effective data. Subsequently, the system further averages selected effective data, and adopts average value data obtained through the averaging, so as to calculate a highly accurate relative velocity. On the basis of the highly accurate relative velocity, the system predicts (forecasts) collision with a specific obstacle (subject target).
The aforementioned collision prediction system makes a prediction (forecast) about collision of the own vehicle, with respect to a detected specific obstacle (subject target). Therefore, if there are a plurality of obstacles (subject targets) that have possibility of colliding with the own vehicle and such obstacles (subject targets) are instantaneously replaced by another obstacle (subject target), the system sometimes fails to make an accurate prediction about a collision. It is often the case that there are a plurality of collision targets that have a possibility of collision with the own vehicle. It is desirable to successively and accurately select, from such collision targets, collision targets having a high possibility of collision with the own vehicle, and to make an accurate prediction about the collision of the selected collision target with the own vehicle.